My wife and I watched ISS over NM tonight (10/17/2016). We both thought that it looked larger than point-like. Can the ISS look like an extended object? Are there docked, or nearby, rockets that could make it appear extended?


The angular width of the ISS seen from Earth's surface is about 0.8 minutes of arc, which is quite close to the angular resolution of the human eye. This is big enough to make it distinctly less "twinkly" than a star, and possibly to perceive some elongation.

  • $\begingroup$ (to me): With naked eye it shows just a dot, but a more steady and much brighter dot than other satellites or stars. But not quite big enough to actually show features. However, I lucked to see a very close pass under ideal lighting, when a Shuttle was docked. At that time it seemed to be a microminature "T" or "v", with a definitely different vertical vs. horizontal proportion. And even very simple field binoculars (8x50) allow you to see the shape like a tiny dragonfly. Hard to keep in view though, as it scoots across the sky at an alarming rate of speed. $\endgroup$
    – PcMan
    Aug 11 at 14:09

Not Really...

Docked or nearby ships would probably not elongate the ship to the naked eye. The main reason that the ISS is so bright is because of its acre of solar panels that tend to reflect a lot of sunlight. However, on-board lights sneaking through the windows are just not bright enough to be visible with the naked eye on the ground. This is why NASA only posts sightings that are happening at dusk and dawn; it is not bright enough in the day, and it is not bright enough at night because the solar panels are not reflecting enough light.

A nearby craft is not bright enough to make the ISS appear elongated because the solar panels are too small to reflect and interior lighting does not generate enough light. However, you can make out some pretty good detail with a simple pair of binoculars.

  • $\begingroup$ Even the Space Shuttle? $\endgroup$
    – Antzi
    Oct 18 '16 at 4:43
  • 1
    $\begingroup$ @Antzi Not really, especially since half of it is black and it doesn't have solar panels at all. If it were brighter, then we would see the elongation, but it's just not bright enough. We wouldn't be seeing any of these anyway since they are now out of commission. $\endgroup$ Oct 18 '16 at 6:33

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